Image display devices such as color TVs and color monitors typically reproduce colors by performing additive color mixing of RGB primary colors. Such image display devices include a matrix-driven image display device (see, for instance, Japanese Laid-Open Patent Application No. 3-78790/1991; published on Apr. 3, 1991).
First, matrix driving will be described in reference to FIG. 10. The matrix-type structure is broadly used in liquid crystal image display devices, EL image display devices, PDP (Plasma Display Panel) image display devices, and the like. It is, however, noted that components of an image display device may be differently named in another type of image display device. In the present application, names of components used in describing the structure of a matrix image display device conform to those of a liquid crystal panel.
As shown in FIG. 10, a matrix image display panel is provided with (i) source bus lines 100 that are vertically provided and in parallel to each other and (ii) gate bus lines 200 that are perpendicular to the respective source bus lines 100.
The source bus lines 100 are connected, at an edge of the image display panel, to a source driver 300. From this source driver 300, video input signals are transmitted to respective pixels. The gate bus lines 200 are connected, at an edge of the image display panel, to a gate driver 400.
The source driver 300 stores video input signals supplied to the respective source lines, and writes the video signals into the gate bus lines 200 that are turned on by the gate driver 400. The gate driver 400 turns on the gate bus lines 200 one by one, so that images are displayed on the entirety of the image display panel.
For color image reproduction, the source bus lines 100 are typically connected to orderly-arrayed R-color, G-color, and B-color pixels, and also to the source driver 300. The source driver 300 supports color image reproduction, so that input lines r-line, g-line, and b-line, which correspond to R, G, and B, receive R, G, and B color video signals, respectively.
FIG. 11 shows video signals supplied to the source driver 300. As in this figure, video input signals are arranged in such a manner that, corresponding to the input lines r-line, g-line, and b-line of the source driver 300, video signals R supplied to R-color pixels, video signals G supplied to G-color pixels, and video signals B supplied to B-color pixels are successively provided in line with time series.
The video signal R(i) (i is an integer) is a video signal supplied to an i-th R-color pixel that is counted in the direction that the gate bus lines are aligned and counted from an R-color pixel firstly turned on. In a similar manner, the video signal G(i) is a video signal supplied to an i-th G-color pixel that is counted in the direction that the gate bus lines are aligned and counted from a G-color pixel firstly turned on, and the video signal B(i) is a video signal supplied to an i-th B-color pixel that is counted in the direction that the gate bus lines are aligned and counted from an B-color pixel firstly turned on.
Each output terminal of the source driver 300 one-to-one corresponds to a group of source bus lines 100 for R, G, or B color, and this allows the image display panel to reproduce color images.
Some source drivers for color display have two inputs to each of R, G, and B color groups. In such a source driver, RGB video input signals supplied to odd lines are separated from RGB video input signals supplied to even lines.
That is, the video input signals shown in FIG. 11 are separated into (i) odd-line video input signals made up of video signals R(2n−1), G(2n−1), and B(2n−1) and (ii) even-line video input signals made up of video signals R(2n), G(2n), and B(2n), as shown in FIG. 12 (n is an integer). As FIG. 13 illustrates, the video input signals thus separated are supplied to odd source bus lines 100 and even source bus lines 100.
When the video input signals are supplied from the source driver 300 as above, the RGB signals are simply separated into odd-line signals and even-line signals, at the stage of input to the source driver 300. On this account, such a driver that separate the video signals and input the same to the pixels is also regarded as a driver having three types of input terminals.
In the meanwhile, an image display device that reproduces images using not less than four primary colors (RGB primary colors and at least one other primary color) has been proposed. Such an image display device adopting not less than four primary colors can set, on a CIE chromaticity diagram, a color reproduction range outside of the reproduction range of the RGB primary colors, so that the color reproduction range of this image display device is wider than that of an image display device adopting RGB primary colors.
The image display device adopting not less than four primary colors has typically adopted a dedicated source driver which has not less than four input types corresponding to not less than four primary colors.
As shown in FIG. 14, to perform image reproduction with multiple primary colors on a J-primary-color (J is an integer not less than 4) image display panel 500, a timing controller 600 that controls a source driver 510 and a gate driver 520 receives video signals (J-primary-color video signals) of J types. On this account, the source driver 510 is a source driver that is dedicated to multiple primary color display and has J input types.
However, such a dedicated source driver having not less than four input types is not in widespread use. A typical source driver has RGB (three) input types. On this account, adopting the source driver dedicated to multiple primary colors increases the manufacturing costs of the image display device.